[349] SCIENTIFIC MANUAL. 63 



common bayberry and the tallow tree of Nicaragua, however, 

 the fat, being solid at ordinary temperatures, requires heat 

 for its extraction. The principal source of commercial 

 vegetable oils, are the seeds of flax, cotton, hemp, sunflower, 

 colza, pea-nut, butter nut, the castor bean, etc., in which the 

 per cent, of oil ranges from 10 to 70. The principal dif- 

 ference between the fatty and the volatile oils as indicated 

 by their names, is found in the non-volatile character of the 

 former, and the volatility of the latter. Fatty oils dropped 

 upon paper leave a grease spot, while the volatile oils en- 

 tirely evaporate, leaving no trace of grease. 



"The proportion of fat in certain vegetable products is 

 given by Wolff and Knop, as follows : 



Maize fodder (green) 0.5 Indian corn 7.0 



Red clover (green) .0.7 Wheat 1.5 



Cabbage 0.4 Rice 0.5 



Pea-fodder (dry) 2.0 Oats 6.0 



Clover hay 3.2 Peas , 2.5 



Wheat staw. 1.5 Barley 2.5 



Average of all the grains. 2.6 Winter rye 2.0 



Potato (Irish) 0.3 Pumpkin.. 0.1 



Turnips 0.1 Beet .*. 0.1 



The Albuminoids or Protein Bodies are classified in three 

 groups. The type of the first is albumen, which is found 

 nearly pure in the white of an egg ; of the second, fibrin, 

 represented by animal muscle; of the third, casein, or the 

 curd of milk. 



Animal Albuminoids differ very little from the vegetable 

 from which they are primarily derived. In both the living 

 or undecayed vegetable and animal matters they are prin- 

 cipally soluble in water, but are very readily rendered in- 

 soluble by coagulation. 



They differ from the carbo-hydrates in having in addition 

 to carbon, hydrogen and oxygen, 15 to 18 per cent, of ni- 

 trogen, some sulphur, and often a small amount of phos- 

 phorus. Together they constitute in plants the whole 



